Fuse functioning mechanism



Sept. 9, 1952 H. L. ROSENBERG FUSE FUNCTIONING MECHANISM 2 SHEETS SHEET l Filed March 25, 1949 n i Ilm "Il M fl Il 1 f//M fin". W. 5 V A du. n/ u. w

Syvum/Mofo Herher LRnael-Lherg M/yMW/ mi Sept' 9, 1952 H. l.. ROSENBERG 2,609,753|

FUSE FUNCTIONING MECHANISM Filed March 2s, 1949 2 SHEETS-SHEET 2 HePhEr-L Rn.senhEr5 WW1. Myw;

.Patented Sept. 9, 1952 UNITED STATES PATENT OFFICE l (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 4757) 3 Claims.

The invention described herein may be manufactured and used by or for the Governmentl for governmental purposes without the payment of any royalty thereon.

This invention relates to improvements in fuses of the type which have a small delay in functioning after impact with a target thereby permitting the continued travel of a projectile armed with one of' the improved fuses a desired distance before being subjected to the action thereof.

One of the principalobjects of the invention is the provision ofV an impact fuse which is especially adapted to effect the optimum performance of explosive projectiles used against aircraft and other targets of a similar character.

Another important object of this invention is the provision of a fuse which will utilize centrifugal action after impact as the force for actuating the fuse whereby the time of fuse functioning may be controlled after impact in accordance with mathematical deductions derived from the laws governing centrifugal force.

With the foregoing and such other objects in view as will hereinafter more fully appear, the invention resides in the novel arrangement and combination of parts and in the details of construction set forth in the yfollowing description and deiined in the appended claims.

In the drawings accompanying this speciflcation and forming a part thereof.

Figure l is a longitudinal sectional view of one form of fuse constructed in accordance with the present invention;

`Figure 2 is a longitudinal sectional View of a modification of the fuse shown in Figure 1,

Figure 3 is a cross sectional view taken upon the line 3-3 of Figure 2;

Figure 4 is a longitudinal sectional view of another form of fuse constructed in accordance with the present invention;

Figure 5 is a cross sectional view taken upon line 5 5 of Figure 4; and

Figure 6 is a cross sectional view taken upon line 6'6 of Figure 4;

Figure 7 is a cross sectional view taken upon the line 1-1 of Figure 1;

Figure 8 is a longitudinal cross sectional view taken upon the line 8-8 of Figure 1.

The several forms of fuse constructions shown in the drawings are intended for use with rotated projectiles and are each so constructed as to function, after action is initiated through impact, with a target, in a manner that will introduce a desired delay in the fuse action after impact. The delay referred to is designed t0 accomplish fuse action when the projectile occupies a position relative to the target to be most effective when detonated and is predetermined in accordance with the following factors deduced as shownY by way 0f one example.

Assume:

Based upon the assumptions of (a), (c) .and (d) it follows that the distance of 9 of (c) will be traversed by the projectile in time t=3/8000 sec.

It is well known that: Y

Where: F=centrifugal force in lbs. M :mass

r=distance (c. g. of rotors Figs 1 and 2 or of ring pin Fig. 4 and axis of shell rotation) V=1inear velocity along orbit of rotation N=R. P. M.

R=`the general expression of r or radius of orbit of rotation but '/rNR V-w So by substituting in (l) 2. M1r2NZT 900 3.l4)2(35,000)2Mr 900 3. =13.60 10MrV If the rotors of Figures 1 and 2 or the ring pin of Figure 4 are free to move, the acceleration of the c. g. thereof perpendicular to the axis of the shell is: i Y 4. F

i a "'M- Where a=pcceleration perpendicular to the axis of the `s ell 3 Substituting F from (3) in (4) 5. a l3.6i) l(lZl/Ir but 8. S=1/2 a. av, t2

Substituting a av. of (7) and t of above rassumptions in (S) :l 6 THe/ 53 )2 S XISXlOX 2 8000 but S the distance the rotors of Figures 1 and 2 Or firing of 'Figure 4 moveto effect deton'ation of the detonator is r2-.r1

If F2 is the force of impingement ofthe firing pin and detonator then from (3) 12. f'2=13.;0 '106 Mrz As the relative striking velocity Vs of the firing pin anddetonator is l lFrom the above it will be noted that the factors affecting fuse functioning and delay may be utilized to control the essential fuse components-to act in acordance with predetermined desirable results. v.

ReferringA now more particularly to the drawings and specifically Vto the'form of fuse disclosed in Figure 1 vthere is shown a die Icast or otherwise formed fuse body Vlllyof any suitable material. f The -body I may befOrmed for attachment to the nose 4of a projectile as by the external threads Il arranged adjacent lthe lbase thereof as shown 'and may be internallythreaded as indicated at I2 for engaging'compler'nentary threads on a booster cup I4 for retaining the booster, cup in the. booster Well of fuse body I0. The booster cup,is conventionally charged with a chargel of tetryl or similar explosive.

A rotor assembly generally designated IS is tion thereof for housing a detonator assembly `positioned within an internalcavity of the fuse 1- body I0 intermediatethe booster and 'nose portion. of the fuse and comprises a rotor housing l1, vwhich may be a die cast aluminum-base alloy' or any similar material, and a sleeve I8 of brass or the like aflixed l-to and enclosing thev housing Il is. snugly tteclfinto the fuse. body cavity as shown. llhe housing Il is.; a generally cylindrical block provided With-a diametral lslot I9 de- 23 charged with any desirable priming mixture. The rotor element may be rotated upon itspins 2| so as to bring the detonator assembly 23 into line with a booster lead 24 centrally located in the bottom of housing l1 thus establishing the usual explosivertrain through the fuse.

A ring pinl 25 afxedA within the fuse as shown is adapted to be impinged by the detonator assembly 23 through the opening 26 in rotor element 2B as the rotor element swings about its pivots 2l to bring the detonator assembly into line with booster' lead 24.

The noseportion of the fuse body is formed with an axial' bore 2'! communicating with the interior cavity of the fuse body within which a plungerlZf and rotor release block 29 are slidably positioned ininterconnected relation by pivot ,bar 30 andjlcvers 3l as shown whereby inward axial movement of plunger 28 will eiectoutward axial movement of Irotor release block, 29. In

the unarmedconditionrof the fuse thefplunger 28, rotor release block 29VA and rotor element '2d occupy, the relative positions shown in Figure 1. Althoughthe linkage for electing conjoint opposed movement of the plunger 2S and rotor release block` 29' is shown as being comprised of the pivot bar 3l) and levers 3| it Will be understoodhthat any suitable `linkage adapted toi'accomplish this `rmrpose may be used. Ifv desired the rotorelement may be additionallyv locked in the unarmed position shown in 'Figure y1by pins 82 VadaptedY to be v moved into Aunlocking positionY under" the actionv of centrifugal force against the spring 33 ina conventional'manner.'

In operation lthe rotor release block 29 will be designed to have more inasslthantheplunger 28 and Will therefore remain in the position'shown inlFigure 1 under the action of the force of setbackduring passage ofthefuse on a projectile through the bore of a gun in firing. If theffuse is provided with the locking pins 32 `these pins Will disengage the rotor element 20 under` the action of centrifugal force during thepassage of the 'fusethrough the bore as is Well understood. During flight Iof the projectile the '-creepfforce acting on the rotorrelease block 29vwill be-overlcome 'by' the 'fr'af'itionalI resistance movement thereof underfthis force through the engagement of the rotor element l25J therewith under the action of centrifugal force.- `Upon impact with a target the plunger 28' is driven axially inward removing the rotor release `|bloclc29 through linkage 3lr303| from the path` vofmovement of rotor element A2li.V Under the force-of centrifugal action tlrerotor'element 2l) rotates on'pins 2| impinging thefdetonatorZS uponijlring pin 25 when the de tonation train-Nyle, 'and l5v are n in alignment. The desiredtime-delay' Willdepend upon 'the timer'equred lforthe detonation train to become aligned which may be `controlled.

`*by the formulae `above derived; A delay suicient to give a 9 inch penetration in the type of' target referred to may for examplelbe obtained under the assumptions usedv in deriving the forrnulae by adjusting r2 to equal 2.83 times r1.' in

' this fuse where 'r2 is the distance between Athe' axis 0f lrotation and firing 'position Iof the center of gravity of vrotor element 23 and r1 is thedistance between the axis of rotation and unarrnedpo'si-y tionV of the center of. gravity of the rotor elelment 21%.; 1

, In the modiioationillustrated by Figure of Y t the drawings there isshown a die cast or other- Wise formed fuse, body of any suitable material. The body v34 may be formed for attachment to the nose ofi a projectile as by external threads35 arranged adjacent the base thereof as shown, and may be internally threaded las indicated at 36 for engagingcomplementary'threads on a booster cup 31 -for retaining the booster cup rin `the booster well of fuse body 35. The booster 'cup is conventionally charged' with a charge 38 of tetryl or similar explosive. AV rotor assembly generally designated 39 is positioned within an `internal cavity of the fuse body i4-intermediate f the booster and nose portion of the fuse and comprising a rotor housing 43 which may be a die cast aluminum base alloy or similar material, a sleeve 4I of brass or the like afxed to and enclosing the housing 40 is snugly fitted into the fuse body cavity as shown. The housing 4i! is a generally cylindrical block provided with a diametrical slot 42 designed to receive a disc shaped rotor element 43 pivoted on either side by pivot pins 44 journalled in suitably aligned journalled wells 45 formed in the side walls defining slot 42. The rotor element 43 is formed with a bore for housing a detonator assembly 46 charged with any desirable primary mixture. The rotor element may be rotated upon its pins 44 so as to bring the detonator assembly 46 into line with a booster head 46a centrally located in the bottom of housing 39 thus establishing the usual explosive train through the fuse. The nose of the fuse body is formed with an axial bore 41 having a `plunger 48 slidably housed therein The plunger 48 comprises a narrow stem portion 49 slidable in a reduced section of the bore 41 having one end as at 50 slidably xed in the enlarged portion of the axial bore 41. The opposite end of the stem 49 is provided with an enlargement 5I slidably fitted in the bore 52 of a keyhole slider 53 which is slidably mounted in a transverse slot 54 communicating with the internal cavity of the fuse body 34 and the axial bore 41. The downward movement of plunger 48 is prevented by the rotor 43 until the recess 58 of the detonator assembly is aligned with the plunger 43. The keyhole slider 53 is provided with an enlarged opening 55 communicating with the bore 52. At one end of the keyhole slider is fastened an L-shaped firing pin 60 projecting downwardly into the slot 42a and inwardly toward the detonator so that when the fuse is in armed position said firing pin will be in alignment with the opening 59 in the rotor 43. The rotor element is locked in the unarmed position by the pins 53 adapted to be moved into unlocking position under the action of centrifugal force against the spring 51 in a conventional manner. l

In operation the enlargement 5I of the plunger 48 upon set back in the gun will engage a matching section 6| in the rotor and prevent movement of the rotor until the projectile leaves the muzzle of the gun. The rotor centrifugal lock pins 55 now move outward and the rotor 43 then swings into armed position, bringing the opening 59 of the detonator 46 into alignment with the firing pin and the recess 58 into alignment with the enlargement 5| of the plunger 48.

Upon impact the plunger 43 is driven downward causing the enlargement 5I to enter the recess 58 and the stem 49 of the plunger to be positioned in the bore 52 of the keyhole slider 53. The keyhole slider is now free to move under the impetus of centrifugal force and the firing pin 6G carried by the keyhole slider is driven into the detonator through the opening 53. The desired time of delay will be determined by the time of firing pin travel which can be calculated in accordance with the formulas derived above.

Figure 4 of the drawing illustrates another fuse employing the principles of this invention in which there is shown a fuse body El' threadedly engaged to an axially bored nose portion 62. The base of said body may be internally threaded as at 63 for engaging complementary threads on a booster cup 64 for retaining the booster cup in the booster well of the fuse body El. The booster cup contains a conventional charge 65 of tetryl or similar explosive. A transverse slot is formed in the top portion of the body IBI as at EB in which is slidably fitted a keyholed slider 61 having a firing pin 68 aflixed to one end opposite a detonator 69 projecting from said body and in communication with said booster. A plunger 1li in the axial bore `1| of the nose portion has a thin section 12 and an enlarged end portion 12a normally positioned and retained in the bore 'I3 of the keyholed slider by a pair of centrifugal pins 14 in a transverse slot 15 in the body 6I immediately below and in communication with the transverse slot 63. The centrifugal pins being held centrally of said body by a frangible pin 16. In operation the set back of the plunger 1G will prevent movement of the centrifugal pins 14. As the projectile leaves the muzzle of the gun the pins 14 move outwardly.

Prior to impact with the target the plunger 16 is prevented from entering the transverse slot 15 by a combination of creep force and friction between the keyholed slider and the enlarged end portion 12a. On impact with the target the plunger is driven down so that its thin section 12 passes through the keyholed slider. The slider with its ring pin 68 is now free to move under the impetus of centrifugal force to puncture the detonator V(i9, starting the detonation wave that travels through the explosive train. The time of delay depends on the desired time of firing pin movement calculated in accordance with the above formulas.

I claim:

1. In a time delay fuse for projectiles comprising va hollow body having an axial bore in the nose thereof, booster means in the opposite end of said body, firing means in said body, rotor Y means including detonator means positioned in operable relationship to said firing means in said hollow body intermediate said nose and said opposite end, said rotor means having its center of gravity initially spaced from the axis of rotation, releasable locking means positioned within said bore comprising a pivoted bar supporting a forwardly directed lever 1on one end and a rearwardly directed lever on the other end, each of said levers supporting a mass normally in alignment with said axial bore, the mass supported by said rearwardly directed lever normally extending into the path of travel of said rotor and restraining the same against movement caused by centrifugal force prior to impact, said levers moving in opposite directions upon impact to release said rotor to the action of centrifugal force, said time delay being determined by the time required for the center of gravity of said rotor to travel a distance equal to a constant times the initial distance of said center of gravity relativ-e vin operable relationship to said ring pin, the

center of gravity of said rotor being initially spaced from the axis of rotation, said-pivoted rotor` having. locking means released by' centrifugal force and rotatedtoward' said ring pin under the inuence of said centrifugal force, said axial bore having a plunger positioned therein and pivotallyconnected to a rotor release block of greater mass than said plunger, said rotor release block engaging said pivoted rotor-upon set back Vand restraining it' against action of centrifugal force prior toV impact, thel time of delay after impact being'determined .by the timev re- 18 greater massthan vsaid plunger, said rotor release block reacting to the force of set back. to

, restrain said rotor against the action of cenquired for the center of'g'ravity of said rotor to Ytravel-a Ydistance equal Yto Ya. constant Ytimes the initial distance' of said center of gravityl relative to saidax-is of'rotatiori. ,y ;y

3. Ar time delay fuse for a projectile comprising a hollow body having an axial bore in the nose thereof, booster means positioned in the base of said body, rotor means carrying a det-` onator and pivotally supported in a cavity intermediate said axial bore and said base, the center of gravity of saidv rotor means being initially spaced from the axis of rotation, a ring pin transversely positioned in' said cavity in operable relationship to said rotor meansg'said axial bore having a plunger positioned` therein and pivotal'ly vconnected to' a rotor release 'block of trifugal force prior to impact, said Vrelease block holdingsaid rotor inA spaced relationship to said tiring pin, said plunger upon impact withdrawing said releasel block to free said rotor tothe action of centrifugal force to imp inge saidfdetonat'or upon said firing pin, the time of Ydelay after impact being determined by the time re- `quired for the center of gravity of said rotor to travel a distance equal to a constant times the initial distance of said center of gravity relative to said axis of rotation.

REFERENCES CITED vThe fol-lowing references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain Oct. 26, 1925 Y nI-IEIEB'IT;RT L. VYROSENBERG. 

